Diamond tool



United States DIAMOND mm Jan Taeyaerts, Villa Park, 111., assignor toPrecision Diamond Tool Company, a corporation of Illinois No Drawing.Application June 2, 1951, Serial No. 229,658

4 Claims. (Cl. 12539) is a sintered mixture of metal powder resulting ina P composition of matter having qualities and characteristicsespecially suited for employment as the holding means for a diamond.

The perfection of a diamond tool for cutting or dressing materials suchas non-ferrous and precious metals, vitreous material and the like, haslong been a problem in the art that has not been satisfactorily solved.With the diamond but partially embedded in the matrix, the problem oftightly securing the diamond under all conditions of usage is adiflicult one of completely satisfactory solution. Moreover, in the useof the tool considerable heat is generated which means that the toolmust either be cooled by the employment of a coolant or the cuttingspeeds must be reduced to keep the generation of heat within the rangeof dissipation of heat for if the diamond becomes too hot it does causemore rapid than normal deterioration and wear.

It is a more particular object of this invention, therefore, to providea tool in which the matrix is of such character that the diamond is atall times firmly held and in fact remains in firm contact with thediamond not only to hold the same but to provide for more effective andefiicient dissipation of heat.

Another object is to provide a tool having a matrix the coeflicient ofexpansion of which is not greater than that of diamond.

Still another object is to provide a tool the matrix of which of suchcharacter that when sintered under pressure it alloys with the diamondso that there is a direct bonding with the diamond.

Other objects and advantages will become apparent from the followingdescription and the appended claims, it being understood that thedisclosure hereinafter made is exemplary and that it is not intended tolimit the invention thereto but to cover all products falling within thespirit and scope of the invention as defined in the appended claims.

Tools of the character here described are generally well known andcomprise a shank or shaft which is usually of steel on or in one end ofwhich is secured one or more diamonds through the medium of some bondingor holding material commonly referred to as the matrix. We are hereconcerned only with the composition of the matrix.

The matrix is herein compounded to have a coefficient of expansion nogreater than that of diamond and preferably has a coetficient ofexpansion less than that of diamond. A matrix with those characteristicswill not, when the tool is in use and as a result becomes heated, expandaway from the diamond thereby loosening its grip on the diamond and thuspermitting initial slight movement or shifting with resultant workingloose of the atent 0 "cc: 16AM Patented Aug. 30, 1955 diamond as thetool continues to be employed. Moreover, a matrix having such acoefiicient of expansion permits of more eifective heat dissipation fromthe diamond because tight contact with the diamond is maintained.

I have found that a composition composed of 64% iron powder and 36% ofhydrogen reduced nickel powder sintered while under pressure results ina matrix having a coefficient of expansion not higher than that ofdiamond, in fact, even lower for the coefficient of expansion of such aproduct is .8 l0 C. which is somewhat lower than 1.18Xl0- C. which isthe coefficient of expansion of diamond.

Not only does the above described matrix have a coefficient of expansionwhich is not greater than that of diamond, but it has been discoveredthat the matrix gives a most desirable, highly sought after but in thiscase entirely unexpected result. It has been found that the compositiongiven above by way of example, when sintered at the necessarytemperature which is approximately 1850 F., actually alloys with thediamond held therein. Much so-called wetting of diamonds is claimed bymanufacturers and patentees, but tests reveal that diamonds when removedfrom the matrix of those products for which wetting of the diamonds isclaimed are no different than they were before embedding in the matrix.When embedded in this matrix, however, in its powdered form and heat andpressure applied to the powdered matrix to sinter the same, a coating isformed on the diamond that cannot be removed by the use of acids orother methods short of burning and thus indicates that there is anactual alloying of the carbon of the diamond with the metals of thematrix. There is thus formed a direct and integral bond between thediamond and the matrix, whereby the matrix is able very firmly andrigidly to hold the diamond. Equally if not more important is the factthat this direct, integral bond causes much more efficient heatdissipation and thus materially reduces the deterioration anddestruction of the diamond that is otherwise wrought when the diamondbecomes heated due to use of the tool.

Cooperating with the direct and integral bonding of the matrix and thediamond and serving to preclude any breaking of the bond is the factthat the matrix has a coeflicient of expansion which is less than thatof the diamond so that there is no stress on the bond but, on thecontrary, as the diamond is heated during use the matrix even holds thediamond more tightly than when cold.

I claim as my invention:

1. A diamond tool comprising a diamond, a matrix of sintered metalpowder consisting of 64% iron and 34% nickel, and an alloy of thediamond and the matrix forming a direct and integral bond between thediamond and the matrix.

2. A diamond tool comprising a diamond, a matrix of sintered metalpowder comprising approximately 64% iron and 34% nickel, and an alloy ofthe diamond and the matrix forming a direct and integral bond betweenthe diamond and the matrix.

3. A diamond tool comprising a diamond, a matrix of sintered metalpowder having a coefficient of expansion no greater than that of thediamond and including a mixture composed in the main of iron and nickelwith iron constituting the major portion and nickel the minor portion,said mixture being capable of alloying with the diamond, and an alloy ofsaid mixture and the diamond forming a direct and integral bond betweenthe diamond and the matrix.

4. A diamond tool comprising a diamond, a matrix of sintered metalpowder having a coefiicient of expansion no greater than that of thediamond and including a mixture of nickel and iron in the approximateproportions of 1:2, said mixture being capable of alloying with theReferences Cited in the file of this patent UNITED STATES PATENTS1,056,555 Krause Mar. 18, 1913 Koebel Mar. 8, Taylor Dec. 26, DuftschmidJuly 2, Taylor Sept. 17; DeBats Jan. 14, Hinnuber June 2, Kott Jan. 16,Lindquist May 28,

1. A DIAMOND TOOL COMPRISING A DIAMOND, A MATRIX OF SINTERED METALPOWDER CONSISTING OF 64% IRON AND 34% NICKEL, AND AN ALLOY OF THEDIAMOND AND THE MATRIX FORMING A DIRECT AND INTERGRAL BOND BETWEEN THEDIAMOND AND THE MATRIX.